Picture this: a mountain of a man — over seven feet tall, by the looks of it — stands in the ambulance bay entrance of a hospital. Clutched in his hands are the feet of a small woman who is dangling, fully conscious, with her head pointed straight at the floor. She appears to be entirely okay with the situation. A flustered doctor commands the man to unhand her — but the giant protests:

"This is my wife," he insists. "I have to hold her this way."

This is the scene that cardiologist Louis F. Janeira encountered at the beginning of a rather unusual afternoon shift. Over at Discover, Janeira recounts what happened next. You'll have to head there to read the account in its entirety, but here's a little preview to whet your appetite:

"Yes, I was here yesterday," she said. "Remember? With the slow heartbeat?"

And then it came to me. Her name was Mary, a woman in her mid-60s. She had arrived at the ER the day before with complete heart block, caused when the electrical system connecting the atria to the ventricles fails because of scarring, infection, or heart attack. As a result, the heart slows dramatically.

Mary's heart rate had been under 40 beats per minute instead of the 60 to 80 that would be considered normal in her age group. She was having recurrent fainting spells and seizures. This giant hadn't been with her then, and I had called a colleague for urgent implantation of a pacemaker, which generates rhythmic electrical pulses that prevent slowing of the heartbeat. Within minutes she had been taken from my ER to a laboratory where she was fitted for the device.

I approached the couple slowly. "I didn't expect to see you so soon," I said leaning over, trying to see her face. "Didn't you have your pacemaker implanted yesterday?"

"Yes," she said. "I had the surgery yesterday. Everything went well, and I went home this morning."

"Everything was good until about half an hour ago," Jason said. "She coughed and then collapsed."

"But I don't understand why you're keeping her upside down," I said.

"I picked her up and put her on our bed," Jason explained. "She regained consciousness for a few seconds. She tried to get up but went out again and fell behind the bed. I picked her up by her ankles and she came to."

"I still don't get it," I said.

"If Jason puts me in bed or upright, I faint again," Mary told me. "We've tried it four times now, and every time he changes my position, I go to la-la land."